1. Field of the Invention
The present invention generally relates to wastewater septic systems and, more particularly, to a valve structure used in a recirculating sand filter system having particular application in residential and small commercial installations.
2. Background of the Invention
Recirculating sand filters for waste water septic systems are used where drainage fields are inadequate or not practical. Waste water flows to a septic tank which provides initial treatment of the wastewater. The septic effluent is discharged into a recirculating pump tank which is provided with a pump controlled by a timer to periodically dose a recirculating sand filter. After the effluent is distributed over the sand filter, the filtrate is collected and directed back through the recirculating pump tank where a recirculation valve either returns it to the pump tank or discharges the effluent for final treatment and disposal. Typically, the effluent that is discharged is chlorinated before final discharge.
In the past, due to the complexity and cost of recirculating sand filter water treatment systems, such systems have been primarily limited to medium to large commercial applications. There is, however, a need for water treatment systems of this type for smaller commercial or residential applications wherein the usual drainage field is inadequate or not pracitcal.
U.S. Pat. Nos. 3,789,986, 3,957,642 and 4,011,162 to Oldham et al. disclose a treatment system for finishing sewage effluent generated from private dwellings. Incoming effluent is dumped onto a tray containing sand. The effluent is filtered by the sand and then drops into a reservoir through holes in the tray. A pump in the bottom of the reservoir pumps the fluid up to a sprayer which sprays the effluent down onto the sand filter for refiltering. A float controls the angle of a trough which extends partially under the sprayer. When the liquid level in the reservoir exceeds a predetermined limit, the trough is pivoted such that part of the spray from the sprayer is directed to an outlet pipe.
U.S. Pat. No. 3,717,251 to Hampton discloses an apparatus for filtering solids such as sewage. A float valve, rigidly connected to an arm member, is used to control a wash pump. The wash pump is shut off as a result of the float rising with the liquid level in the tank. The float actuates electrical contacts.
U.S. Pat. No. 3,202,174 to Rudelick discloses a float actuated fill valve. The valve prevents the liquid in a vessel from falling below a predetermined minimum level as well as preventing the liquid in the vessel from exceeding a predetermined maximum level. The valve comprises a free floating ball and a tubular member. The ball mates with valve seats at either end of the tubular member.
U.S. Pat. No. 2,944,669 to Schaaf discloses an effluent regulator for septic tanks. The regulator is bottle shaped and rises with the level of the sewage in the tank. U.S. Pat. No. 1,536,063 to Bartlett discloses a liquid treatment apparatus which includes a ball float carried on an angular extension of a pipe.
U.S. Pat. Nos. 4,350,587 and 4,439,317 to Jarrell disclose "on location" sewage treatment systems. In U.S. Pat. No. 4,350,587, an accordian pleated sheet supports a bacteria culture which consumes waste matter that passes through the sheet. These sewage treatment systems employ ozone gas for disinfecting the liquid resulting from treated sewage. U.S. Pat. No. 4,196,082 to Salokangas et al. discloses a combination biological dry toilet and a biological waste water purifying plant in which a pump is used to pump "grey" water over a filter bed. In the Salokangas et al. system, treated water is absorbed in the soil.
U.S. Pat. No. 4,439,323 to Ball discloses a process for discharging septic tank filtered effluent. Waste water is filtered and discharged from a septic tank in predetermined increments.